Disappointing second-quarter earnings and a far-from comforting management conference call were to blame for the dramatic share price tumble.

Facebook missed Wall Street expectations on revenue growth and user numbers. Revenue rose 42% to $13.23 billion but was $70 million short of forecasts. Monthly active users were around 20 million below predictions at 2.23 billion, despite being up 11% on Q2 in 2017.

For most other companies, this would be stellar growth, but Facebook operates in its own universe. And there was scant comfort on the earnings call, where analysts, investors, and journalists were told by CFO David Wehner that growth will continue to slow over the coming months.

Here's what Wall Street is saying about Facebook's earnings:

Credit Suisse

Price target: $225.00 (lowered from $265.00)

As well as a squeeze on revenue and users, Facebook said there will be significant decreases in operating margins in the years ahead. Credit Suisse said this could point to a "new existential crisis."

"CEO Mark Zuckerberg had in the past raised the likelihood of margin compression due to an inevitable mix shift to do more video advertising, so conceptually this is not new," it said.

"That said, we and the Street had assumed at the time that mix shift would arrive on a higher revenue base due to incremental revenue from Facebook Watch and not necessarily due to cannibalization."

Barclays

Price target: $180.00 (lowered from $226.00)

Barclays' note was headlined, "FB Throws Some Napalm On The Fire," and it makes fairly chastening reading for Facebook.

Barclays had two theories for Facebook's gloomy outlook. Firstly, "they don't want to create the perception of getting rich while their product presents issues for society."

The second theory is a little more troublesome: "There are more serious engagement problems with core Facebook that have materialized recently that they are trying to fix," Barclays said.

"The truth is likely somewhere in the middle," it added.

Goldman Sachs

Price target: $205 (lowered from $225)

Goldman remained relatively bullish on Facebook, suggesting it saw the warning signs in previous messages from Zuckerberg and other senior executives.

"Despite always having a conservative posture, management commentary about decelerating topline growth during a quarter where the company fell short of ad revenue for the first time is what has led to the stock's after-hours performance," it said.

Pivotal

Price target: $140 (lowered from $142)

Pivotal said the earnings were "OK" and did not materially impacted its modelling. But it warned that the GDPR privacy laws in Europe and other regulatory threats mean that more pain could be on the way.

"Our view is that the company is far from 'out of the woods' as the bundling of consent for Facebook to use consumer data with access to the platform appears to be an aggressive interpretation of GDPR, and one that might be more subject to eventual regulatory action," it said.

Macquarie Research

Price target: $190 (lowered from $220)

Analysts at Macquarie said Facebook's earnings reflect management making structural changes for the future.

"This should be welcomed, because in our view, the LT [long-term] trajectory is not on solid ground, as growing privacy issues, ramping gov't regulation, and ever-evolving user habits present LT existential threats to FB's health," they said.

As an interesting side note, Macquarie added that there has never been a better case for Facebook to introduce a subscription model.

"The potential for FB to offer consumers an ad-free subscription option is at the highest level ever. Beyond privacy, we are seeing consumers more and more comfortable paying for digital content," it said.